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    <script>
        var r = parseFloat(prompt("请输入圆锥的底面半径"));
        var h = parseFloat(prompt("请输入圆锥的高"));
        var π = 3.1415926;
        var s = 1 / 3 *( π * r * r) * h;
        alert(s);
        
        
    </script>
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